Browse these pages to learn more about the Interdisciplinary Centre for Ancient Life (www.ical.manchester.ac.uk) at the University of Manchester. This blog is written and regularly updated by palaeobiologist Professor Phil Manning (STFC Science in Society Fellow).
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Wednesday, 26 March 2014

X-rays brighter than a million Sun's show fossil leaf chemistry preserved for 50 million years!

Palaeontologists, geochemists and physicists from the University of Manchester, (UK) Diamond Lightsource
(UK) and the Stanford Synchrotron Radiation Lightsource (USA) have published a new paper in the Royal Society of Chemistry journal, Metallomics,
that has shed new light, in fact one of the brightest lights in the universe,
on 50 million year old fossil plants.

Dr. Nicholas Edwards, a postdoctoral researcher at the
University of Manchester and a lead author on the paper said: “The
synchrotron has already shown its potential in teasing new information from
fossils, in particular our group’s previous work on pigmentation in fossil
animals. With this study, we wanted to use the same techniques to see
whether we could extract a similar level of biochemical information from a
completely different part of the tree of life.”

False colour image of copper (red) and zinc (green) distribution
within a modern leaf (A. pseudoplatanus).
The distribution of these metals defines the vascular system. Image width ~3
mm. Image from data acquired at the Diamond Light Source, the UK’s national
synchrotron science facility.

Dr. Edwards went on to say
“To do that we needed to test the chemistry of the fossil plants, to see
whether the fossil material was derived directly from the living organisms or
degraded and replaced by the fossilisation process. We know that plant
chemistry can be preserved over hundreds of millions of years. Today we even
rely on this preserved chemistry as the fossil fuels that power our society.”

However, this is just the “combustible” part, until
now no-one has completed this type of study of the other biochemical components
of fossil plants, such as metals.

By combining the unique capabilities of two
synchrotron facilities, our team were able to produce detailed images of where
the various elements of the periodic table were located within both living and
fossil leaves as well as being able to show how these elements were combined
with other elements.

The work shows that the distributions of copper, zinc
and nickel in the fossil leaves were almost identical to those in modern leaves.
Each element was concentrated in distinct biological structures such as the
veins and the edges of the leaves. Also, the way these trace elements and
sulfur were attached to other elements was very similar to that seen in modern
leaves and plant matter in soils.

X-ray false colour composite image
(Cu = red, Zn = green, and Ni =blue) of a 50 million year old leaf fossil.
Trace metals correlate with original biological structures. This leaf was
skeletonized by insects which have left behind characteristic trumpet shaped
feeding tubes as shown in the inset. Inset: copper only map revealing detail of
feeding tube and fine scale veins. Feeding tube chemistry matches the leaves.
Image width ~17 cm. Data collected at Stanford Synchrotron
Radiation Lightsource (SSRL), a national user facility operated by Stanford University on
behalf of the U.S. Department of Energy, Office of Basic Energy Sciences.Image reproduced courtesy of the Royal Society of Chemistry, Edwards et al 2014, Metallomics, DOI:10.1039/C3MT00242J.

Professor Roy Wogelius, also of the University of
Manchester and one of the senior authors said: “This type of chemical
mapping and the ability to determine the atomic arrangement of biologically
important elements such as copper and sulfur can only be accomplished at a
synchrotron. In one beautiful specimen, the leaf has been partially eaten by
caterpillars and their feeding tubes are preserved on the leaf. We see this behaviour
with modern caterpillars. The chemistry of these fossil tubes remarkably still
matches that of the leaf on which the caterpillars fed.”

The data from a suite of other techniques performed at
the University of Manchester has lead the team to conclude that the chemistry
of the fossil leaves is not wholly sourced from the surrounding environment as
has previously been suggested but represents that of the living leaves.

Another modern day connection suggests a way in which
these specimens are so beautifully preserved over millions of years. We think that copper may have
aided preservation by acting as a ‘natural’ biocide, slowing down the usual
microbial breakdown that would destroy delicate leaf tissues. This property of
copper is utilised today in the same wood preservatives that you paint on your
garden fence before an inclement season.

Dr. Uwe Bergmann a co-author on the paper from Stanford,
also remarked: “Part of what I do involves detailed measurements of the
physics of how plants actually harness light energy using transition metals.
Here, we are able to show what metals were present, and where, within extremely
old plants- and this just may let us understand, eventually, how the
complicated physics of life has developed over long periods of time.”

Fine scale false colour X-ray map of the Cu distribution within a modern leaf (left) compared to a 50 million year old fossil leaf (right). Primary, secondary, and tertiary venation comparable to the modern leaf can be resolved in the Cu distribution even after 50 million years of ageing. Data acquired at the Diamond Light Source (left panel), the UK’s national synchrotron science facility, and the Stanford Synchrotron Radiation Lightsource (right panel), a national user facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences. Image widths: left ~2.5 mm, right ~10 mm. Image reproduced courtesy of the Royal Society of Chemistry, Edwards et al 2014, Metallomics, DOI:10.1039/C3MT00242J.

Dr. Bart van Dongen, another University of Manchester
geochemist stated: “There is a sharp contrast in the chemistry of the
fossils from that of the rock in which they are entombed. This is true for both
the trace metals and the organic compounds. The organic part of the chemistry
clearly shows a plant derived component.” Dr. Nicholas Edwards added: “This opens up the possibility
to study part of the biochemistry of ancient plants, so in the future it may
enable us observe the changes, if any, in the use of metals by the plant
kingdom through geological time.”

It seems the fidelity that fossil leaves already bring to the palaeontological table has been significantly enhanced by these new findings.

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Dr Phil Manning

Dr. Phil Manning is Professor of Natural History and Director of the Interdisciplinary Centre for Ancient Life (www.ical.manchester.ac.uk) at the University of Manchester (UK) and is
also a Research Associate at the American Museum of Natural History (New York)
and a Visiting Scholar at the University of Pennsylvania (USA). In January 2014 he was elected a
Fellow of the Explorer’s Club. Dr. Manning’s research is both broad and interdisciplinary
with active research topics including: biomechanics, geochemistry and elemental
analysis (particularly specialising in synchrotron-based imaging techniques),
application of LiDAR-based imaging to both landscape and skeletal modelling, high-performance
computing work, mechanical analysis of biomaterials (both extant and extinct),
finite element analysis and imaging. Dr. Manning and his team have worked
extensively in the Hell Creek Formation of South Dakota and Montana, but their
field program also includes sites in South America, Europe, Asia, Africa, Australia and the Cayman Islands.

Dr. Manning plays an active role in science outreach,
contributing to open-days, lectures, workshops, fieldwork, etc. He has authored
both children and popular science books and is a regular contributor to public
speaking programs around the world, promoting the public engagement of science.
In 2013 Dr. Manning was appointed as the Science and Technology Research
Council (STFC) Science in Society Fellow, so as to promote science and
technology to as wide an audience as possible.